Improve the quality of standard TV images - I designed this circuit many years ago, based on the claims that the technique would improve the quality of standard TV images. The circuit adds information to the edges of the objects and was reported to bring out more detail. After building and testing . . . Hobby Circuit designed by David A. Johnson P.E.-July 08, 2000

Infrared TV/VCR Remote Booster - This circuit will boost the signal from any infrared TV or VCR remote, extending the range by a factor of 3X. . . . Circuit by Dave Johnson P.E.-October 05, 2005

IR TV/VCR Remote Booster - This circuit will boost the signal from any infrared TV or VCR remote, extending the range by a factor of 3X. . . . Hobby Circuit designed by David Johnson P.E.-October 05, 2005

Low Pass Filter, 3Khz, with an Audio Amp - This circuit uses a switched capacitor filter IC from National Semiconductor to filter signals with frequencies higher than the 3KHz needed for voice audio. The schematic includes an audio amplifier that is designed to drive a standard audio head phone . . . Hobby Circuit designed by Dave Johnson P.E.-June 04, 2000

Microphone On/Off Switch Circuit is Pop Free - This circuit uses a simple technique to eliminate the usual “pop” sound when an electret type microphone is switched on or off. The circuit is completely passive and will work on dynamic and electret type microphones . . . Hobby Circuit designed by Dave Johnson P.E.-February 15, 2002

Miniature Audio Amplifier - This miniature audio amplifier delivers up to 250mW and can be used like a final stage audio amplifier for radio sets. The schematic is very simple: one BC547 transistor controls a balanced power amplifier built with BC337 and BC327. The total amplification is around 15x and is determined by R1, R3 and P1. __ Designed by Popescu Marian

Miniature Class a Amplifier - The philosophy behind this minimalist design has been explained by Flavio Dellepiane on his highly interesting site 1. I have myself written an article about this fleapower amp from Italy in the American magazine AudioXpress 2. All relevant details __ Designed by Aren van Waarde

Miniature FM Transmitter - This miniature transmitter is easy to construct and it's transmissions can be picked up on any standard FM receiver. It has a range of up to 1/4 of a mile or more. It is great for room monitoring, baby listening, nature research, etc. L1 is 8 to 10 turns of 22 gauge hookup wire close wound around a non-conductive 1/4 inch diameter form __ Designed by Andy Wilson

Miniature FM Transmitter #1 - This miniature transmitter is easy to construct and it's transmissions can be picked up on any standard FM radio. It has a range of up to 1/4-mile (Tony van Roon's 400 meters) or more, depending on the line-of-sight, obstructions by large buildings, etc. It is great for room monitoring, baby listening, nature research, __ Designed by Tony van Roon VA3AVR

Miniature FM Transmitter #7 - There is no thrill like the thrill you get from operating equipment you have built yourself. If you have never built a project from a magazine before, let this be your first--you'll see how much satisfaction and fun you can have! __ Designed by Tony van Roon VA3AVR

Mini-Box 2 Watt Amplifier - This amplifier was designed to be self-contained in a small loudspeaker box. It can be feed by Walkman, Mini-Disc, iPod and CD players, computers and similar devices fitted with line or headphone output. Of course, in most cases you will have to make two boxes to obtain stereo __ Contact: Flavio Dellepiane, fladello @ tin.it

Minimalist Discrete Hi-Fi Preamp - Note that the project described here has been superceeded by the new Revision A version. The new circuit uses a dual supply, and does not include the power supply. P05 is ideally suited for this new version. A preamp designed for the minimalist, and having no frills at all is the design goal for this project. It is designed as a preamp for the Death of Zen (DoZ) Class-A power amp (Project 36), and has very low levels of noise and distortion, in a minimum component count, fully discrete circuit. __ Designed by Rod Elliott ESP

Minimum Theremin Kit Schematic - Two identical integrated circuits, U1 and U2, known as "hex inverters" are used for the theremin's primary functions. They are CMOS
(Complimentary Symmetry Metal Oxide Semiconductor) devices, typically used in digital circuits to perform a logic function called "inversion. " Each IC contains six identical sections; thus the term "hex inverter. "

Mixer & Preamplifier for String Instruments - Most of the small musical bands have up to four string instruments like guitars and violins. The signal from the transducers of these instruments should be buffered and sometimes amplified before __ Electronics Projects for You

Mockman 2.0 - This project has returned from beyond the grave for a tune-up. Compressed, harsh, and '80s sounding are fitting descriptions of its sonic character. Yes, it is a niche sound which is quite the opposite of some JFET-based distortions developed by the 'groove, however we feel it is a great time capsule of an era fondly remembered by many. Whether you are looking for a simple weekend project or willing to play a cover of an '80s hard rock anthem, the Mockman will suit your needs. __ Contact: holler @ runoffgroove.Com

Model Train Horn (2-tone) - With this circuit you can electronically simulate the noise of a diesel-train horn. The sound is triggered automatically as the train reaches a desired place on the track so you can produce the sound as the train approaches stations, level crossings, etc. The circuit can be built simply by using one 556 or two 555 timers __ Designed by Tony van Roon VA3AVR

Mono to Stereo Synthesizer / Simulator - This circuit attempts to liven up mono sound sources by simulating a stereo signal. It does this by shifting certain frequencies between left and right to fool the ear. It can often produce a passable mock stereo sound to bring some depth to otherwise flat recordings. Of course, there is no way to produce real stereo sound from a purely mono source unless the synthesizer had a way to tell which direction the original sound came from, but an illusion is generally enough for all but the hard core audiophile. __ Designed by oRbEq

Monoblock Gainclone Amplifier - This is a monoblock Gainclone amp based on a LM3886 IC which is more suited to 4 ohm loads. It will output 70 Watts into 4 ohms. This version also uses a very high capacitance PSU and a snubber. The case is made entirely

MOS Doubler - A cleaner sounding version of an octave up, uses CMOS
Logic IC. Much less distortion than full wave rectifier based octave designs. New design from R. G. __ Designed by Guitar Effect RC Keen

Motorola Hi-Fi power Amp - This is a very simple, low cost, Hi-Fi quality power amplifier. You can build it 5 ways, like it's shown in the table (from 20 W to 80 W RMS).

MP3 Player - This is my MP3/AAC player project. The difference to most other players is that decoding is not done on a specialized IC (like VS1001) , but directly on the microcontroller. It can play MP3 (all bit rates) and AAC (up to ~256 kbps) from SD card in real time. The project is work in progress.

MP3 Player - These schematics are one of three parts needed to build the entire MP3 player. The other two are the 8051 Development Board and IDE Interface.

MP3 Player (Rev C) - Student Project Alert: Many students request this schematic. Many student projects have a scope of work where using this design is legitimate, like this student project where they tried to write ATAPI drivers. For student projects which mandate original hardware design work (not just construction or modification of an existing design), using this large and complex design would be very unwise, as it is more sophisticated than a typical student project.

MP3 Player with IR Remote Control - This MP3 player similar to iPOD shuffle that is based on the latest innovative BU9432 chip from RHOM. It features USB 1.1 / 2.0 Controller, MP3 decoder, system controller for loading MP3 files from a USB flash drive, USB hard drive, USB CD-ROM or USB DVD-ROM drive all in one chip. Once USB flash drive is connected, BU9432 automatically.

MS Stereo Decoder - The schematic diagram of the MS Decoder may look complicated but is actually quite simple. Both the Mid and Side signals are initially buffered by unity gain inverting buffers formed around IC1b and IC2 b. __ Designed by Jules Ryckebusch

Multimedia Speaker - The Dutch magazine Audio & Techniek once published an article about one-way loudspeakers that were based on Audax units 1. Although speakers using just a single full-range unit per audio channel were disregarded in audiophile circles (high intermodulation distortion), they could also have important advantages (excellent imaging). The editors of Audio & Techniek were enthusiastic about the Audax sound; they claimed that the single driver flaws were minor and the advantages were huge. “We never heard so much soundstage for so little money” was their comment. __ Designed by Aren van Waarde

Multi-Melody Generator with Instrumental Effect - This melody generator can generate various English and Hindi tunes as also instrumental effects. Various modes of melodies can be selected through DIP switches.Other advantages are high volume and volume control.IC __ Electronics Projects for You

Multiple Feedback Bandpass Filter - The multiple feedback bandpass filter is a simple looking design, but it is difficult to calculate the values for a given set of parameters. These filters are useful for equalisation, analysis and other tasks such as the Sound to Light converter (Project 62) or even a fully functional Vocoder. For those who have not heard of the vocoder, it is a device that takes a music source as one input and vocals as the other, allowing a guitar, keyboard or complete ensemble to be made to speak or sing. The "speech" from a good vocoder is quite intelligible, and is "ear candy" of the very best kind for experimental musicians. __ Designed by Rod Elliott ESP

Music Box - This circuit produces 10 different tones and by selecting suitable values to change the voltage on pin 5, the result can be quite pleasing. Note: the two unused outputs of the 4017 produce a tone equal to that produced by the 555 when pin 5 has no external control voltage. __ 555-Timer

Music Box - This little novelty uses the PIC PWM output to produce an approximation to decaying sine waves, which sound very much better than fixed amplitude square waves, but its still far from precision function generation!! An LDR provides a simple way to detect when the lid of the music box is opened. Alternatively of course, pin 13 (RB7) can be tied low and a microswitch employed on the power rail. __ Contact: Karen's Microprocessor Projects

Music player built on microcontroller AT91SAM7S256 with ARM core - 1. The player allows: playback wav files in stereo format, 22, 500Hz freqfency, and 8 bits of resolution, display the song titles, display time of songs, the possibility of stopping (pause) and switch songs, the possibility of change __ Designed by Szymon Dyja

Music to light Modulator - The diagram shows how simple the circuit is. The audio signal is applied across the LED of the opto-TRIAC. The potentiometer adjusts the input sensitivity while the resistor is used as protection from high signal peaks.

Musical Electronic Bell - This is a very simple musical electronic bell. This bell not only gets you rid from old irritating noisy bells, but also avoids unwanted disturbances on radio and TV produced by damp waves. These damp waves are generated by electrical devices when they are switched on or off. __ ` Sigmatone

Musical Horn for ATBs - If you are both an all-terrain biker and handy with a soldering iron, then we suggest you build this musical horn which, apart from the fact of having a much pleasanter sound than a simple bell, will usually make passers-by turn to you with a broad smile, so surprised will they be to hear these few notes coming from an ATB or mountain-bike. must register on this site __ Designed by Published in Elecktor July/Aug, 2010

Musical Instrument (Expandable) Graphic Equaliser - This equaliser is designed as a preamp suitable for musical instrumentsguitar, bass and keyboard in particular. Unlike most conventional graphic equalisers, each slider ranges from fully off to fully on, and not the more conventional +/-12dB or so that is normally available. __ Designed by Rod Elliott ESP

Musical Ladybug - Our son Henk is fond of small animalsbees, bugs, waterbugs, frogs, hedgehogs, newts, fishes and toads. They are caught in the gardens and ponds around our house and neatly stored in vessels, jars and containers for careful study. After a few days of confinement they are returned to their natural environment (and in unhappy cases, caught again within a few days). So when we decided to give Henk a radio for his sixth birthday, it could not be a dull grey portable from Radio Shack. For this special occasion we designed the one and only musical ladybug. __ Designed by Aren van Waarde

Musical Light Chaser - This music-operated lighting effect generator comprises five sets of 60W bulbs that are arranged in zig-zag fashion. The bulb sets glow one after another depending on the intensity of the audio __ Electronics Projects for You

Musical Water Shower - Won’t it be nice to have music playing in the background all the while when you take a shower? This simple circuit does the same. It plays different tunes repeatedly for __ Electronics Projects for You

Musical’ Touch’ Bell - Here is a musical call bell that can be operated by just bridging the gap between the touch plates with one’s fingertips. Thus there is no need for a mechanical ‘on’/‘off’ __ Electronics Projects for You

Mute for Big Briar Etherwave® Theremin - This circuit permits the addition of a "mute" switch to the Etherwave® Theremin, useful for placing the theremin in a silent mode without having to turn it off completely. There is no "pop" during the mute-unmute transition. A MUTE STATUS light-emitting diode doubles as a convenient power indicator. The circuit was constructed on a small circuit board installed inside the theremin. The MUTE CONTROL switch __ Designed by Arthur Harrison